There is no information available in the literature on the effect of gamma irradiation on the physical properties of olive oils. Therefore, the objective of this study was to determine the effect of γ-irradiation treatment (0, 1, 2 and 3 kGy), storage time of olives (0, 30 and 45 days), and storage time of extracted oils (0, 6 and 12 months) on physical properties of Syrian Kaissy cv olive oil (SKOO). Refractive index (RI), viscosity and color of olive oils were determined, immediately after extraction and after 6 and 12 months of storage. Results showed that the RI (1.4659 ± 0.0002), viscosity (151.67 ± 1.53 mPa s-1), and color parameters (lightness (L*) (71.51 ± 2.06), redness (a*) (14.65 ± 0.91), yellowness (b*) (56.85 ± 3.27) and overall color difference (ΔE) (53.74 ± 3.97) values of olive oil was significantly (p <0.05) changed by γ-irradiation and storage time. In general, the RI of SKOO was significantly (p<0.05) increased by γ-irradiation and decreased by extended storage time. The viscosity values of SKOO were significantly (p<0.05) decreased by γ-irradiation and storage time. Irradiation treatment and storage time increased significantly (p <0.05) the a* and ∆E values, and decreased significantly (p <0.05) the b* of olive oils. The analytical parameters studied of oil extracted from irradiated and non-irradiated fruits were within the limits established by the International Olive Council (IOC, 2015).

PDF (Download Full text)